休眠session.save（）缺少查询

嗨家伙我建立一个简单的ToDoList（这只是我的项目的开始），应该添加任务到我的日程安排通过使用MAMP作为数据库。我的问题是season.save（）缺少查询中的主键（“id”）; 我有以下代码：主类：休眠session.save（）缺少查询

package Model; 


    import java.util.Date; 
    import java.util.List; 

    import org.hibernate.HibernateException; 
    import org.hibernate.Session; 
    import org.hibernate.SessionFactory; 
    import org.hibernate.cfg.AnnotationConfiguration; 


    //create exception instead of HibernateException ToDoListDAOException 
    public class HibernateToDoListDAO implements IToDoListDAO { 

     SessionFactory factory = null; 
     private static final HibernateToDoListDAO _instanceDAO = new HibernateToDoListDAO(); 


     // no need to do connection or use driver to my sql 
     private HibernateToDoListDAO(){ 
      factory = new AnnotationConfiguration().configure().buildSessionFactory(); 
     } 

     public static HibernateToDoListDAO getInstance() 
     { 
      return _instanceDAO; 
     } 

     @Override 
     public void addMemorandums(items memorandum) throws HibernateException { 
      Session session = factory.openSession(); 
      try{ 
       session.beginTransaction(); 
       //create the query for memorandum members 
       session.saveOrUpdate(memorandum); 
       System.out.println("after save : user id's = "+memorandum.getId()); 

       session.getTransaction().commit(); 
      }catch(HibernateException e) 
      { 
       e.printStackTrace(); 
       if (session.getTransaction() != null) 
        session.getTransaction().rollback(); 
      }finally{ 
       session.close(); 
      } 
     } 

     @Override 
     public void updateMemorandums(items memorandum) throws HibernateException { 
      Session session = null; 
      try{ 
       session = factory.openSession(); 
       session.beginTransaction(); 
       session.update(memorandum); 
       session.getTransaction().commit(); 
      }catch(HibernateException e) 
      { 
       e.printStackTrace(); 
       if (session.getTransaction() != null) 
        session.getTransaction().rollback(); 
      }finally{ 
       session.close(); 
      } 
     } 

     @Override 
     public void deleteMemorandums(items memorandum) throws HibernateException { 
      Session session = null; 
      try{ 
       session = factory.openSession(); 
       session.beginTransaction(); 
       session.delete(memorandum); 
       session.getTransaction().commit(); 
      }catch(HibernateException e) 
      { 
       e.printStackTrace(); 
       if (session.getTransaction() != null) 
        session.getTransaction().rollback(); 
      }finally{ 
       session.close(); 
      } 
     } 

     @SuppressWarnings("unchecked") 
     @Override 
     public List<items> getMemorandums() throws HibernateException { 
      List<items> memorandum = null; 
      Session session = null; 
      try{ 
       session = factory.openSession(); 
       session.beginTransaction(); 
       memorandum = session.createQuery("from todolists").list(); 
      }catch(HibernateException e) 
      { 
       e.printStackTrace(); 
       if (session.getTransaction() != null) 
        session.getTransaction().rollback(); 
      }finally{ 
       session.close(); 
      } 
      return memorandum; 
     } 

     public static void main(String[] args) { 

      @SuppressWarnings("deprecation") 
      String dateTask = "26/11/2016"; 
      items task1 = new items(2012,"football", dateTask , "ball"); 
      HibernateToDoListDAO.getInstance().addMemorandums(task1); 

     } 
    }

项目类：

package Model; 

import java.util.Date; 

public class items { 

    private int id;// primary key that connect to the users 
    private String taskname; 
    private String date; 
    private String note; 


    public items(){ 
     taskname = "basketball"; 
     note = "a fun game"; 
     date = "15/10/2016"; 
     id = 2012; 
    } 

    public items(int id, String taskName, String taskDate, String note) { 
     super(); 
     this.taskname = taskName; 
     this.date = taskDate; 
     this.note = note; 
     this.id = id; 
    } 

    public String getTaskname() { 
     return taskname; 
    } 

    public void setTaskname(String taskname) { 
     this.taskname = taskname; 
    } 

    public String getDate() { 
     return date; 
    } 

    public void setDate(String date) { 
     this.date = date; 
    } 

    public String getNote() { 
     return note; 
    } 

    public void setNote(String note) { 
     this.note = note; 
    } 

    public int getId() { 
     return id; 
    } 

    public void setId(int id) { 
     this.id = id; 
    } 

}

我试图运行这个简单的程序，我得到那个看起来异常，如：

（例外）

Hibernate: insert into items (taskname, date, note) values (?, ?, ?) 
org.hibernate.HibernateException: The database returned no natively generated identity value 
    at org.hibernate.id.IdentifierGeneratorHelper.getGeneratedIdentity(IdentifierGeneratorHelper.java:84) 
    at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:98) 
    at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57) 
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2329) 
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2836) 
    at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71) 
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:267) 
    at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:321) 
    at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204) 
    at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130) 
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210) 
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195) 
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:117) 
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93) 
    at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:677) 
    at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:669) 
    at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:665) 
    at Model.HibernateToDoListDAO.addMemorandums(HibernateToDoListDAO.java:36) 
    at Model.HibernateToDoListDAO.main(HibernateToDoListDAO.java:111)

hibernate.cfg.xml中：

<?xml version="1.0" encoding="utf-8"?> 
<!DOCTYPE hibernate-configuration SYSTEM 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 

<hibernate-configuration> 
    <session-factory> 
    <property name="hibernate.dialect"> 
     org.hibernate.dialect.MySQLDialect 
    </property> 
    <property name="hibernate.connection.driver_class"> 
     com.mysql.jdbc.Driver 
    </property> 

    <!-- Assume test is the database name --> 
    <property name="hibernate.connection.url"> 
     jdbc:mysql://localhost:3306/hit 
    </property> 
<property name="hibernate.connection.username">hit</property> 
<property name="hibernate.connection.password">hit</property> 
<property name="show_sql">true</property> 

<!-- Mapping files --> 
<mapping resource="hibernate.mapping.xml"/> 

</session-factory> 
</hibernate-configuration>

hibernate.mapping.xml：

<?xml version="1.0" encoding="utf-8"?> 
<!DOCTYPE hibernate-mapping PUBLIC 
"-//Hibernate/Hibernate Mapping DTD//EN" 
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 

<hibernate-mapping> 

    <!-- *********** items table ******* --> 
<!-- full class name including the packege name --> 
    <class name="Model.items" table="items"> 
     <meta attribute="class-description"> 
     This class contains the the items details. 
     </meta> 
     <id name="id" type="int" column="id"> <!-- primary key --> 
     <generator class="native"/> 
     </id> 

     <property name="taskname" column="taskname" type="string"/> 
     <property name="date" column="date" type="string"/> 
     <property name="note" column="note" type="string"/> 
    </class> 

    <!-- *********** users table ******* --> 

    <!-- full class name including the packege name --> 

    <class name="Model.users" table="users"> 
     <meta attribute="class-description"> 
     This class contains the users details. 
     </meta> 
     <id name="id" type="int" column="id"> 
     <generator class="native"/> 
     </id> 
     <property name="name" column="name" type="string"/> 
     <property name="age" column="age" type="int"/> 
    </class> 


</hibernate-mapping>

我使用甲基苯丙胺作为我的数据库（MySQL的工作）。问题是，查询只插入三个而不是四个变量（缺少“id”成员）。有人可以帮我解决这个问题吗？

谢谢你们。

来源

2016-11-29 ofer gertz

你需要'id'列作为'自动增量'在你的分贝。正如您正在学习的，现在是熟悉java命名标准的好时机，以下链接http://www.oracle.com/technetwork/java/codeconventions-135099.html –

您必须自动递增表的标识列才能消除此错误。编写alter table查询以使标识列自动递增。这应该可以解决你的问题

来源

2016-11-29 19:47:16 shashwatZing

WOWOW ...它的工作原理。非常感谢您的帮助 –

休眠session.save（）缺少查询

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